Contact copying material



Sept- 8, 1970 M. M. LABES 3,527,666

CONTACT COPYING MATERIAL Filed Dec. 11. 19e? "w x n I4 y a o ad) "ilNfl;

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5 ENTOR. Morti M Lubes www ATTORNEYS.

United States Patent O CONTACT COPYING MATERIAL Mortimer M.`Labes,Rosemont, Pa., assignor to Drexel Institute of Technology, Philadelphia,Pa., a corporation of Pennsylvania Filed Dec. 11, 1967, Ser. No. 689,666

. Int. Cl. B32b 5/18 U.S. Cl. 161-161 5 Claims ABSTRACT F THE DISCLOSUREBACKGROUND OF THE IINVENTION l Prior art copying techniques which havebeen developed to provide a limited number of copies of each sheet tobe' copied have beenprincipally of the photocopy type, requiring alightsource, have required the use of stencils, or'vhave been concerned withthe application of toner Aparticles tovipaper and thelike vby usingcarrier particles which are .electrically charged. The copyingtechniques of the prior art-arethus rather cumbersome, in many.'instances, in requiring expensive equipment, there being rno provisionfor-facilitating the copying of a limited number of sheets in arelatively simple and inexpensive manner. Also,` the priorart-,is devoidof any such copying atechnique whichv is readilyfportable, and thereforeadapted for; usel in environments other than those of a fully vequippedolice:

' SUMMARY on THE INVENTION l Thepre'sent invention `seeks tofulll aneedwhich rexits in the prior art,'in providing a composite pressuresensitive copyingelement in which a carrier layer has 'been impregnatedwithan. image-forming substance, and a transfer layer having a pluralityof-capillary-likepores -fis ladapted to receive the image-formingsubstance from `the carrier layer, when the transfer layer is placedagainst `.Lthe'surface of a sheet to be copied. The surface to becopied'will generally haveaunmarked surface portions, and marked'surfaceportions which are either printed, 'typewrittern or the like.`This invention utilizes the difl ference in porosity between marked andunmarked surface portions, to effect a difference in flow rates of thelimage-forming substance through capillaries which have one end'disposedagainst the sheet to be copied, some of 'l the capillaries terminatingagainst a marked surface por- "tion ofthe sheet to be copied, and otherof the capillaries terminating-against an unmarked :surface portion ofthe 'shee'tto be'copied, such that the rate of ow of the image-`fo'rn'nngsubstance is greater in those capillaries which are disposedwithone end against an unmarked surface `portion of the sheet to becopied'. By applying pressure to thecarrier layer, and appropriatelytiming the applicaftionof suchpressure, an image, either latent oractual A wiyll'appear in either the carrier layer or thecapillarystructured transfer layer, or both, such image beingres'ponsive to the amount of flow of the image-formingsubstancethroughthe capillaries of the transfer layer, hence responsiveto the marked and unmarked surface portions "ofthe sheet to-be copied.

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Accordingly, it is an object of this invention to provide a pressuresensitive copying element having a carrier layer which is impregnatedwith an image-forming substance, a transfer layer having a plurality ofcapillarylike pores therein, with both layers being sandwiched betweenHuid-impermeable layers, which prevent the transfer of an image-formingsubstance from the carrier layer to the transfer layer prior to removalof one of the fluid-impermeable layers.

It is another object of this invention to provide an element as setforth in the object immediately above, wherein that fluid-impermeablelayer which is provided against the transfer layer is readily separabletherefrom.

It is a further object of this invention to provide a novel copyingmethod, wherein a pressure sensitive copying element such as thatdiscussed in the objects immediately above is provided, and whereinpressure is applied to the carrier layer, after the transfer layer isapplied into direct engagement against the surface of a sheet to becopied, and the pressure applied to the carrier layer facilitates theexpulsion of entrapped air from the capillaries of the transfer layer,at a rate dependent on the porosity of the particular surface portion ofthe sheet to be copied, disposed immediately beneath the capillaries,such surface porosity varying between marked or indicia-bearing andunmarked or indicia-free surface areas, leaving an image on either ofthe carrier or transfer layers.

iIt is another object of this invention to accomplish the objectdescribed immediately above, wherein the time period of pressureapplication is discontinued prior to all entrapped air being forced outof any of the capillary pores.

It is a further object of this invention to accomplish the aboveobjects, wherein the image formed on either of the carrier or transferlayers may be either latent or actual.

Other objects and advantages of the present invention will be readilyapparent to those skilled in the art from the following briefdescription of the drawing figures, detailed description of theinvention, and the appended claims.

In the drawings:

FIG. l is a highly enlarged schematic cross-sectional view through acomposite copying element or material of this invention.

FIG. 2 is a view generally similar to that of FIG. 1, but wherein alowermost fluid-impermeable layer has been removed, and the copyingelement has been placed in overlying relation to a printed sheet to becopied, with pressure applied.

FIG. 3 is a fragmentary view taken generally along the line III- III ofFIG. 2, of an image formed in a substantially transparent carrier layerof a copying element of this invention, by complete ow of animage-forming substance from the carrier layer with only partial ow ofthe image-forming substance into some of the capillary pores of atransfer layer, leaving a generally T-shaped image in the carrier layer,corresponding generally to a marking or indicia on the surface of thesheet to be copied.

FIG. 4 is a view generally similar to that of FIG. 3, but taken alongthe line IV-IV of FIG. 2, wherein differences of depth of image-formingsubstance in capillary tubes create a difference in image shadingbetween portions of the transfer layer which overlie printed portions ofthe sheet to be copied, and portions of the transfer layer which overlieunprinted portions of the sheet to be copied.

Referring now to the drawings in detail, reference is first made to FIG.l, wherein there is illustrated a composite copying element, generallydesignated by the nuumeral 10, disposed on a planar surface 11.

The composite element 10 includes a carrier layer 12, which isimpregnated with an image-forming substance 13, a transfer layer 14, anupper fluid-impermeable layer 15, and a lower fluid-impermeable layer16.

The carrier layer 12 may be constructed of any material suitable forliquid impregnation and retention, such as a fibrous or sponge-likematerial, or the like. The material 12 may be compressible and porous,such as a felted material, or may be of sponge-like Neoprene, latexfoam, or of fibrous glass construction.

The image-forming substance 13 may comprise an ink or dye or any othersuitable marking or coloring substance. Additionally, the image-formingsubstance 13 may be substantially colorless, leaving no visibleindication to the naked eye, but which, when treated with chemicals,chemical solutions, heat or light would be transformed from a latentimage to an actual image.

The transfer layer 14 is generally a soft capillary membrane materialhaving an ordered pore structure preferably, but not limited to therange of 102 to Il()8 pores per centimeter2. An exemplary but notlimiting example of such transfer layer material may comprise thatcommercially available material known as Nuclepore.

The `Huid-impermeable or non-porous layer 15 may comprise an integralskin portion of the carrier layer 12, or may comprise a separate layerof any suitable fluidimpermeably film. Exemplary materials for the layer15 are those such as polyvinyl chloride, cellophane, or any of thevarious resin films, or the like, having desirable fluid-impermeablecharacteristics.

The lower Huid-impermeable or non-porous layer 16 is generally adistinct layer manually separable from the transfer layer 14, and may beconstructed from any suitable material such as those set forth above asexemplary constructions for the layer x15.

In the fragmentary microscopic sectional schematic view of FIG. l, thetransfer layer 14 is illustrated as having capillary pores 17, 118, 20,21 and 22, each of the pores being separated from one another by a wallportion 23.

With reference to FIG. 2, the element is illustrated as having the lowerfluid-impermeable nonporous layer 16 removed therefrom, with the element10 being disposed in overlying relation to the sheet 24, which is to becopied, with the lower-most open ends of the pores 17, 18, 20, 21 and 22of the transfer layer 14 disposed against an upper surface 25 of thesheet to be copied 24.

Ihe sheet 24 may comprise a sheet of paper or the like, having printed,typed, or other indicia-bearing surface portions 26, 27, and 28 thereon,and unmarked or indiciafree surface portions such as those 30 and 31. Itis to be noted, that while the sheet 24 is referred to as a sheet ofpaper or the like, any structure having indicia or other markingsthereon may be copied, as long as such structure is sufficiently porous,to permit the passage of air from capillary ends disposed thereagainst.

While the printed surface portions 26, 27 and 28 are illustrated in FIG.2 as being disposed directly beneath the capillary pores 17, 20 and 22,for exemplary purposes, it is to be noted that a given printed or markedsurface portion, such as, for example, the letter T may be disposedbeneath hundreds or more individual capillary pores.

In a copying operation, with the non-porous sheet 16 removed from thecomposite element 10, and the element 10 when being applied in overlyingrelation to a printed sheet 24 or the like, disposed on a generallyplanar surface 11, pressure P is then applied to the upper surface ofthe element 1'0, preferably by engagement of a pressure plate (notshown) against the upper surface of the layer 15, such that pressure istransmitted to the carrier layer 12, thereby forcing the image-formingsubstance 13 into the capillary pores 17, 18, 20, 21 and 22. As theimage-forming substance 13 is forced into the capillary pores, capturedair or the like is forced outwardly, through the lower ends of thepores, as illustrated in FIG. 2, through the porous sheet 24, which isto be copied.

It has been found, that the porosity of a porous sheet 24 is decreasedwhen such a sheet is marked or bears other indicia, such as is effectedin a printing, typing or the like operation. In fact, it has been foundthat in some instances, the porosity of an unprinted portion of a sheetof material is twice as great as the porosity of a printed portion ofthe sheet of material. Employing this feature to advantage, it has beenfound that upon application of a pressure P in the manner abovedescribed, the imageforming substance 13 will descend or flow intocapillary pores 18 and 21 which are disposed above unmarked o1'indicia-free surface portions of the sheet 24, at a greater rate thanwill the substance 13 ow through the capillary pores 17, 20, and 22which overlie marked or indiciabearing surface portions 26, 27, and 28of the sheet 24. If the porosity ratio of unmarked sheet portions tomarked sheet portions is represented by a factor of two to one, in agiven time interval during which pressure P is applied to the element10, substantially twice as much imageforming substance 13 will descendinto the capillary pores 18 and 21 as will descend into the capillarypores 17, 20 and 22.

It will be noted that the timing of the application of pressure P to theelement 10 should be carefully controlled, such that the image-formingsubstance 13 descending in the capillary pores 18 and 21 will notdescend an amount sutlicient to contact the surface portions 30 and 31of the sheet 24, to undesirably mark the same.

When the desired predetermined length of time has passed, the element 10may be removed from the sheet 24, and the layers 12 and 14 may then beseparated, thereby allowing the image-forming substance 13 which is thenpresent in those layers to dry upon contact with air, substance 13having previously been prevented from air contact and hence from dryingin the composite element 10 due to the presence of the fluid-impermeablelayer 15 and 16.

The image formed in the layer 14 may appear substantially as that shownin FIG. 4, with the composite area formed by the liquid substance 13which is dried in the plurality of capillary pores 17, 20, and 22 whichwere disposed over marked or indicia-bearing surface portions of thesheet 24 being substantially lighter than the area. formed by theimage-forming substance which is of greater depth in the pores 18 and21, such difference in depth of dried image-forming substance giving avisual indication such as that illustrated in FIG. 4 for the letter T,in which the lighter area comprising the T formation is effected by acomposite formation of pores having an image-forming substance of lesserdepth, and the outlining area for the letter T is effected by acomposite of those pores of greater depth of dried image-forming substance 13. It will be apparent that the image evidenced by FIG. 4 is anegative image as compared to the image or marking originally present onthe surface 25 of the sheet 24 which is copied.

It is conceivable that the transfer layer 14 may be constructed of adouble thickness sheet having an upper layer (not shown) which ispenetrated by the image-forming substance 13 pressing into all of thecapillary pores 17, 18, 20, 21, and 22, and having a lower layer belowthe mating surface for such layer portions, such that the image-formingsubstance 13 penetrates below such mating surface only through thosecapillary pores 18 and 21 which are not disposed over marked surfaceportions of the sheet 24 to be copied. In such a structure, uponseparation of the two layer portions of the transfer layer 14, thenegative image illustrated in FIG. 4 would be formed only by a compositeof a plurality of pores 18 and 21, in which the image-forming substance13 had penetrated, leaving a void or completely blank area such as thatwhich comprises the T formation in FIG. 4, formed by separating thelower layer portion of the layer 14 from its upper layer portion priorto penetration of the pores 17, 20, and 22 of the lower layer portion bythe image-forming substance 13.

After discontinuing the application of pressure P, and separation of thecarrier layer 12 from the transfer layer 14 and the fluid-impermeablelayer 15, a positive image is left on the carrier 12, by theimage-forming substance 13 which is not received completely withincapillary pores of the transfer layer 14, but which remains Within thecarrier layer 12, such as that shown disposed above capillary pores 17,20, and 22 in FIG. 2. Upon separation of the carrier layer 12 from theother layers, and drying of the image-forming substance 13 upon aircontact, a mirror image of the printed indicia 26, 27, and 28 on thesurface of the sheet 24 appears on the under surface of the carrierlayer 12. However, should the carrier layer 12 be, for example, oftransparent construction, and viewed from above, along the section lineIII-III of FIG. 2, a positive image would be available on the uppersurface of the layer 12, directly corresponding to the original markingor indicia which appears on the upper surface 25 of the sheet 24 whichis copied. With reference to FIG. 3, there is illustrated the View whichwould appear along the section line III-III, or upon the upper surfaceof the layer 12, if a letter T appeared on the surface 25 of the sheet24, the letter T being formed by the residual image-forming materialwhich remains within the carrier layer 12, disposed directly above thosecapillary pores which are, in themselves disposed directly abovecomparable portions of a marking or indicia represented by the letter Ton the surface 25 ofthe sheet 24.

As has been mentioned above, should the image-forming substance be of atype adapted to leave only a latent image, after termination of theapplication of pressure P to the composite element 10, it may bedesirable to subject either of the layers 12 or 14 to additionaloperations or processes, in order to develop a visible image thereonresponsive to the differential flow rate of the image-forming substance13 through the capillary pores. Such later procedures may or may not benecessary depending upon the type of image-forming substance 13 which isutilized.

It will be apparent that the terms indicia and marking should vfbe readin the broadest sense, to include any marking, printing, writing, etc.,which may be desired to be copied. Also, the various materials set forthherein are exemplary only, and this invention is not intended to belimited to the specific materials, or to specific manners of operation.In some instances it may be desirable to place the sheet to be copied inoverlying relation to the composite element 10, and to exert pressureonto the sheet which is to be copied, which would be transferreddownward for compression of the carrier layer, and consequently resultin a rise of image-forming substance into the capillary pores. Suchmodifications and others as Well, are to be considered to be within thescope of this invention.

The particular embodiments illustrated and described are exemplary only,and are not intended to limit the scope of this invetnion, as defined inthe appended claims.

What is claimed is:

1. A pressure-sensitive copying element comprising a carrier layerimpregnated with an image-forming substance, a transfer layer disposedwith one surface against an adjacent surface of said carrier layer; saidtransfer layer comprising a material having a plurality ofcapillary-like pores therein, extending between opposite layer surfacesthereof, said carrier layer and said transfer layer each being providedwith fluid-impermeable means on opposite non-adjacent surfaces.

2. The element of claim 1 wherein said uid-impermeable means compriseseparate film layers.

3. The element of claim 1, wherein that fluid-impermeable means which isprovided on said transfer layer is readily separable from said transferlayers.

4. The element of claim 3, wherein said transfer member has an orderedpore structure in the range between 102 and l08 pores per centimeterz.

5. The element of claim 3, wherein said carrier layer is of fibrousconstruction.

References Cited UNITED STATES PATENTS 3,020,171 2/1962 Bakar et al.ll7-36.l 3,336,867 8/1967 Levine et al. lOl- 468 FOREIGN PATENTS 702,156l/ 1965 Canada.

ALFRED L. LEAVITT, Primary Examiner M, F. ESPOSITO, Assistant ExaminerU.S. Cl. X.-R.

lOl- 468, 473; 117-37, 35.6, 301, 36.7; 161-406

